A wind farm is a group of wind turbines, which are located in the same area and which are used for producing electric power. Typically, individual wind turbines of a wind farm are interconnected with a medium-voltage power collection system and a communications network. At an electric substation, a medium-voltage electrical current is increased in voltage by means of a transformer in order to feed the resulting high voltage power to a high voltage transmission system.
A large wind farm may consist of a few dozen and up to several hundred individual wind turbines and cover an extended area of hundreds of square kilometers. Typically, each individual wind turbine is equipped with an individual control unit, which controls and regulates the operation of the wind turbine for instance based on an individual power setpoint being indicative for the actual electric power generation of the wind turbine. Furthermore, there is a superordinate wind farm control unit, which monitors the operation of the entire wind farm and of the individual wind turbines. Via a data line to the individual control units, the superordinate wind farm control unit can collect information regarding the individual wind turbines and transmit appropriate control signals to the respective individual control units. For instance, it is known to stop all wind turbines of a wind farm through a central stop command of the wind farm control unit and to cut off the wind farm completely from the grid.
Specifically, the superordinate wind farm control unit manages a correction of the overall wind farm power output, such that an appropriate overall power production of the wind farm can be achieved. This is accomplished by a superordinate power setpoint for the overall power production. In order to realize an appropriate overall wind farm power output, based on the superordinate power setpoint an appropriate individual power setpoint has to be determined for each wind turbine. This determination is typically carried out by means of a separate algorithm.
The conversion from (a) a superordinate power setpoint value, which may also be called a wind farm power reference value, to (b) individual power setpoints, which may also be called wind turbine reference values, yields a large span of possibilities and given degrees of freedom corresponding to the number of wind turbines in the wind farm. Functions used for this conversion can take several things into account, but the goal is typically to control the wind farm as one power plant, instead of controlling all individual wind turbines separately.
In order to adapt this kind of collective control it is necessary to have a tool that interconnects the whole wind farm regarding the setpoint distribution. This means that an assigned setpoint for a first wind turbine will be a direct function of the assigned setpoint of a second wind turbine in the wind farm. One option for realizing this would consist in a sequential or iterative setpoint calculation. Thereby, the wind turbine settings would be managed in a “top to bottom” running program. Doing this however would complicate the respective algorithm further in particular in terms of data management, and will also lead to slower program.
Based on the above considerations, there may be a need to provide a procedure for effectively managing the dependencies between different individual wind turbine set points.